Confidence is high after last week's excellent performance and 2-0 victory against Leeds United.
That win lifted us back into seventh in the Premiership but Glenn warns that City will also be on a high after toppling Sunderland at the Stadium of Light last week.
"Going to Birmingham is always a tough, tough game," said Glenn. "They will be buoyant after their win at Sunderland. They will be up for it and the crowd will be up for it but we go there with confidence.
"Not only the win but the performance against Leeds was probably the best we've played with the ball all season.
"We have to try and reproduce that away from home which is a lot tougher.
"It will be a different style of game but we have to be bold and try to assert ourselves on them over the 90 minutes."
We've had a mixed bag away from home so far.
Glenn added: "Some of our performances have been good away from home, Liverpool comes to mind, and some not so good like Sunderland.
"We've got a chance to put it right and look for our third win away from home after doing well at Charlton and Blackburn.
"We've got to look to consolidate after Leeds."
Glenn Hoddle says the lads will run out at St Andrews this afternoon with a spring in their step.